test: 补充知识处理、检索与 Agent 回归用例

覆盖切块、向量检索、工具调用和历史预算；模型相关用例使用桩。

backend/tests/agents/test_chat_agent_transfer_prompt.py

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+"""
+Copyright 2024-2026 ChatterMate
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+"""
+
+from unittest.mock import MagicMock, Mock, patch
+from uuid import uuid4
+
+import pytest
+from sqlalchemy.orm import Session
+
+from app.agents.chat_agent import ChatAgent
+
+
+def build_agent(transfer_to_human: bool) -> ChatAgent:
+    """A ChatAgent with everything external stubbed, to read the prompt it built."""
+    agent_data = Mock()
+    agent_data.name = "Support"
+    agent_data.jira_enabled = False
+    agent_data.transfer_to_human = transfer_to_human
+    agent_data.ask_for_rating = False
+    agent_data.ticketing_enabled = False
+    agent_data.instructions = ["You are a helpful assistant"]
+
+    storage = Mock()
+    storage.get_session_state.return_value = {"status": "active"}
+
+    with patch('app.agents.chat_agent.get_db') as mock_get_db, \
+         patch('app.agents.chat_agent.JiraRepository') as mock_jira_repo, \
+         patch('app.tools.knowledge_search_byagent.KnowledgeSearchByAgent', return_value=Mock()), \
+         patch('app.agents.chat_agent.EncryptedPostgresAgentStorage', return_value=storage), \
+         patch('app.agents.chat_agent.settings.DATABASE_URL', "mock://test"), \
+         patch.dict('os.environ', {}, clear=True):
+        mock_get_db.return_value = iter([MagicMock(spec=Session)])
+        mock_jira_repo.return_value.get_agent_with_jira_config.return_value = agent_data
+
+        return ChatAgent(
+            api_key="test-key",
+            model_name="gpt-4",
+            model_type="openai",
+            org_id=str(uuid4()),
+            agent_id=str(uuid4()),
+            customer_id=str(uuid4()),
+            session_id=str(uuid4()),
+        )
+
+
+def prompt_of(agent: ChatAgent) -> str:
+    """The built prompt on one line: the blocks are indented heredocs, so a
+    sentence is only contiguous once the wrapping whitespace is collapsed."""
+    instructions = agent.agent.instructions
+    text = "\n".join(instructions) if isinstance(instructions, list) else instructions
+    return " ".join((text or "").split())
+
+
+class TestTransferToHumanPrompt:
+    """The switch is a setting on one agent. Said plainly ("transfer to human is
+    disabled"), the model repeats it back as a fact about the business - an agent
+    answering questions about its own product then tells customers the product
+    cannot hand chats to a human, which is false."""
+
+    def test_disabled_transfer_is_scoped_to_this_chat(self):
+        prompt = prompt_of(build_agent(transfer_to_human=False)).lower()
+
+        assert "cannot hand this conversation to a human" in prompt
+        # It must say what this is NOT, or the model generalises it
+        assert "not a fact about the business or its product" in prompt
+        # and leave the customer somewhere to go
+        assert "open a ticket" in prompt
+        # Capability questions are answered from the knowledge base, not the switch
+        assert "answer from the knowledge base, not from this setting" in prompt
+
+    def test_enabled_transfer_still_offers_the_handover(self):
+        prompt = prompt_of(build_agent(transfer_to_human=True)).lower()
+
+        assert "ability to transfer this conversation to a human agent" in prompt
+        assert "cannot hand this conversation to a human" not in prompt